<s>
Red	B-Operating_System
Storm	I-Operating_System
is	O
a	O
supercomputer	B-Architecture
architecture	O
designed	O
for	O
the	O
US	O
Department	O
of	O
Energy	O
’s	O
National	O
Nuclear	O
Security	O
Administration	O
Advanced	B-General_Concept
Simulation	I-General_Concept
and	I-General_Concept
Computing	I-General_Concept
Program	I-General_Concept
.	O
</s>
<s>
Cray	B-Device
XT3	I-Device
.	O
</s>
<s>
Red	B-Operating_System
Storm	I-Operating_System
is	O
a	O
partitioned	O
,	O
space	O
shared	O
,	O
tightly	O
coupled	O
,	O
massively	B-Operating_System
parallel	I-Operating_System
processing	I-Operating_System
machine	O
with	O
a	O
high	O
performance	O
3D	O
mesh	O
network	O
.	O
</s>
<s>
The	O
processors	O
are	O
commodity	O
AMD	B-General_Concept
Opteron	I-General_Concept
CPUs	O
with	O
off-the-shelf	O
memory	O
DIMMs	B-General_Concept
.	O
</s>
<s>
When	O
deployed	O
in	O
2005	O
,	O
Red	B-Operating_System
Storm	I-Operating_System
’s	O
initial	O
configuration	O
consisted	O
of	O
10,880	O
single-core	O
2.0GHz	O
Opterons	B-General_Concept
,	O
of	O
which	O
10,368	O
were	O
dedicated	O
for	O
scientific	O
calculations	O
.	O
</s>
<s>
The	O
remaining	O
512	O
Opterons	B-General_Concept
were	O
used	O
to	O
service	O
the	O
computations	O
and	O
also	O
provide	O
the	O
user	O
interface	O
to	O
the	O
system	O
and	O
run	O
a	O
version	O
of	O
Linux	B-Application
.	O
</s>
<s>
The	O
Red	B-Operating_System
Storm	I-Operating_System
supercomputer	B-Architecture
was	O
designed	O
to	O
be	O
highly	O
scalable	O
from	O
a	O
single	O
cabinet	O
to	O
hundreds	O
of	O
cabinets	O
and	O
has	O
been	O
scaled-up	O
twice	O
.	O
</s>
<s>
In	O
2006	O
the	O
system	O
was	O
upgraded	O
to	O
2.4GHz	O
Dual-Core	B-Architecture
Opterons	B-General_Concept
.	O
</s>
<s>
This	O
resulted	O
in	O
a	O
peak	O
performance	O
of	O
124.4	O
teraflops	O
,	O
or	O
101.4	O
running	O
the	O
Linpack	B-Application
benchmark	O
.	O
</s>
<s>
A	O
second	O
major	O
upgrade	O
in	O
2008	O
introduced	O
Cray	B-Device
XT4	I-Device
technology	O
:	O
Quad-core	B-Architecture
Opteron	B-General_Concept
processors	O
and	O
an	O
increase	O
in	O
memory	O
to	O
2	O
GB	O
per	O
core	O
.	O
</s>
<s>
Top500	B-Operating_System
performance	O
ranking	O
for	O
Red	B-Operating_System
Storm	I-Operating_System
after	O
each	O
upgrade	O
:	O
</s>
<s>
Red	B-Operating_System
Storm	I-Operating_System
is	O
intended	O
for	O
capability	O
computing	O
.	O
</s>
<s>
The	O
Portals	B-Operating_System
network	I-Operating_System
programming	I-Operating_System
API	I-Operating_System
is	O
used	O
to	O
ensure	O
inter-processor	O
communication	O
can	O
scale	O
as	O
large	O
as	O
the	O
entire	O
system	O
,	O
and	O
has	O
been	O
used	O
on	O
many	O
different	O
supercomputers	B-Architecture
,	O
including	O
the	O
Intel	O
Teraflops	O
and	O
Paragon	B-Device
.	O
</s>
<s>
The	O
compute	O
processors	O
use	O
a	O
custom	O
lightweight	B-Device
kernel	I-Device
operating	I-Device
system	I-Device
named	O
Catamount	B-Operating_System
,	O
which	O
is	O
based	O
on	O
the	O
operating	O
system	O
of	O
ASCI	B-Device
Red	I-Device
called	O
"	O
Cougar	O
"	O
.	O
</s>
<s>
A	O
userspace	O
implementation	O
of	O
the	O
Lustre	B-Application
file	O
system	O
,	O
named	O
liblustre	O
,	O
was	O
ported	O
to	O
the	O
Catamount	B-Operating_System
environment	O
using	O
the	O
libsysio	O
library	O
to	O
provide	O
POSIX-like	O
semantics	O
.	O
</s>
<s>
This	O
filesystem	O
client	O
ran	O
in	O
the	O
single-threaded	O
Catamount	B-Operating_System
environment	O
without	O
interrupts	O
,	O
and	O
only	O
serviced	O
IO	O
requests	O
when	O
explicitly	O
allowed	O
by	O
the	O
application	O
,	O
to	O
reduce	O
jitter	O
introduced	O
by	O
background	O
file	O
system	O
operations	O
.	O
</s>
<s>
Red	B-Operating_System
Storm	I-Operating_System
was	O
decommissioned	O
in	O
2012	O
.	O
</s>
